Hybrid solar cell achieves 78% efficiency in near-infrared region

Korean researchers have made progress in improving the performance of perovskite solar cells.

They have developed a hybrid technology that maximizes near-infrared light capture and energy conversion efficiency.

Researchers at the Korea Advanced Institute of Science and Technology (KAIST) say this innovation paves the way for the commercialization of next-generation solar cells. Moreover, it promises a bright future for solar energy and global technological advancement.

This research broke new ground by significantly increasing the energy conversion efficiency of the hybrid device to 24.0% from 20.4%.

Hybrid solar technology

They have developed a highly efficient and stable hybrid solar cell that can capture near-infrared light.

It is special because it can absorb not only visible light (the light we see), but also near-infrared light, which is invisible to the human eye. The expanded light absorption range allows the solar cell to generate more electricity from sunlight.

They combined two types of materials: perovskite and organic photosemiconductors.

“The research team has proposed and refined a next-generation organic photosemiconductor hybrid device structure that will complement perovskite materials’ limited absorption of visible light and extend the absorption range to the near-infrared region,” the press release noted.

Works in wet conditions

Most perovskite solar cells can only absorb visible light (wavelengths of 850 nanometers (nm) or less), which limits their efficiency. This limitation prevents cells from using approximately 52% of all available solar energy.

To unlock the full potential of solar energy, they created a hybrid device that combines the strengths of perovskite and organic materials with a bulk heterojunction.

This innovative approach resulted in a solar cell capable of absorbing light up to the near-infrared region.

Moreover, the researchers identified and solved the electronic structure problems by introducing a dipole layer, resulting in a high-performance solar cell.

By adding a subnanometer dipole layer, they improved charge transport and near-infrared absorption, increasing the current density to 4.9 mA/cm².

In a solar cell, internal quantum efficiency (IQE) measures how efficiently it converts incoming photons (particles of light) into electrical current.

According to the press release, the device achieved a record high IQE of 78% in the near-infrared region.

Interestingly, the device has proven to be durable and reliable, maintaining over 80% of its maximum performance for over 800 hours even in humid environments.

“Through this research, we have effectively solved the charge storage and energy band mismatch problems faced by existing perovskite-organic hybrid solar cells, and we will be able to significantly improve the energy conversion efficiency while maximizing the near-infrared capture performance, which will be a new breakthrough,” which can solve the problems of mechanochemical stability of existing perovskites and overcome optical limitations,” said Professor Jung-Yong Lee in a press release.

This innovative approach significantly improves the overall efficiency of solar cells, resulting in increased electricity production.